The protective role of zinc in cancer: A potential chemopreventive agent

Abstract

The essentiality of trace mineral element-zinc in human health has been recognized over several decades. Zinc is known to participate in the activation of approximately 300 enzymes and is involved in the regulation of over 2,000 zinc-dependent transcription factors, which are involved in DNA synthesis, protein synthesis, cell division, and other metabolisms. Early evidence suggested that zinc deficiency can cause growth retardation, delayed sexual maturation, depressed immune response, and cause abnormal cognitive functions. A large body of epidemiological and clinical studies demonstrates that zinc deficiency is associated with the increased risk of some cancers, such as prostate, esophageal and oral cancers. The data from in vitro and in vivo studies clearly suggest that zinc may play a protective role in the development and progression of cancer; however, the exact mechanism of zinc action in carcinogenesis is not fully understood. A large number of studies have demonstrated that zinc deficiency induces inflammatory cytokines and oxidative stress, apoptosis and cellular dysfunction, disrupts DNA-protein interaction, and depresses the functioning of T cell mediated immune response. Zinc supplementation reverses these adverse effects, suggesting that the anti-tumor effect of zinc could be potentially due to its anti-inflammatory, anti-oxidative, DNA and protein integrity, T-cell immune response, and other properties. Therefore, zinc may be implicated as a chemopreventive agent as summarized in this article.